Removed the now useless signal.SIGCHLD [skip hazardlib]
Removed the now useless signal.SIGCHLD [skip hazardlib]


Former-commit-id: 01074a3828c37508dfd17adf05e38f8e451fbf85
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine